Оценка влияния метеорологических параметров на изменчивость площади и толщины морского льда в Карском море

The reduction of the sea ice area in the Arctic is one of the most notable consequences of climate change, with the Kara Sea contributing about 5 % to the overall reduction. The aim of this study is to assess the impact of changes in climatic conditions on the reduction of the area and thickness of the sea ice in the Kara Sea and the possibility of using the established dependencies for climate forecasting. The article provides quantitative estimates of the relationship between interannual changes in the sea ice thickness and sea ice extent in the Kara Sea and climate changes in the region and the remote influence of the sea surface temperature in the tropical North Atlantic for 1979–2019. The paper uses observation data obtained at meteorological stations, ERA5 reanalysis and data on the sea ice extent from the Arctic and Antarctic Research Institute website. In summer, the melting of sea ice is largely due to changes in the surface air temperature (correlation coefficient from –0.57 to –0.91). In winter, the ice thickness depends on the sum of frost degree-days (r = –0.80). The temperature regime, in turn, is determined by the radiation balance, namely, by the variability in the long-wave flow due to the increase in the water vapor content. On the basis of the relationships established, a linear regression model is proposed for forecasting the sea ice area with a lead time of about three months. The model is effective and statistically significant. The paper considers the remote influence of the sea surface temperature anomalies in the North Atlantic tropics on the ice coverage of the Kara Sea. The response of the sea ice extent to the sea surface temperature in the low latitudes is 30–34 months late. The significant correlation between the anomalies can serve as a basis for predicting the sea ice area in the Kara Sea with a lead time of up to three years.В работе приведена количественная оценка влияния метеорологических параметров, таких как температура воздуха, влагосодержание атмосферы, нисходящее длинноволновое излучение, на толщину и площадь льда в Карском море. На основе установленных связей предложена регрессионная модель прогноза площади льда Карского моря с заблаговременностью 3 месяца. Рассмотрено удаленное влияние на площадь льда в Карском море аномалий от средней температуры поверхности океана в тропиках Северной Атлантики. Установленная значимая корреляция может послужить основанием для прогноза площади льда Карского моря с заблаговременностью до трех лет

Effect of RemarsGel on the condition of tooth enamal

The article deals the possibilities of remineralization of tooth enamel when using the "RemarsGel" toothpaste are considered. Calculations of changes in the concentration of calcium ions in tooth enamel due to the formation of brushite are made.В статье рассмотрены возможности реминерализации зубной эмали при использовании зубной пасты «РемарсГель». Произведены расчёты изменения концентрации ионов кальция в зубной эмали за счёт образования брушит

Оценка многолетней изменчивости толщины припая в морях Российской Арктики по данным полярных станций

The warming process in the Arctic steadily continues and significantly affects the entire regime of sea ice cover development. Most of the sea ice thickness studies are based on numerical modeling and information obtained using satellite radar altimetry such that these estimations require validation by means of contact measurements. However, the comparison of data is difficult due to the irregularity and locality of measurements. This makes contact measurements at polar stations highly relevant. In this study, contact measurements were carried out by drilling for each 10-day period during winter season, they are quite accurate and have a long observations series in the same regime conditions from year to year, allowing one to assess the long-term variability of fast ice thickness. In this study, we analyzed the data series of the fast ice thickness and the surface air temperature at 16 Roshydromet land-based polar stations in the Russian Arctic Seas. The data series were taken into account from the beginning of regular measurements (the end of the 1930s, the year of the beginning varies depending on the station) to 2020 for the period November–May. Observations for the recent 15-year period (2005–2020) are compared with those prior to 2004 (from the 1930s–40s). Since 2005 sea ice thicknesses at the moment of maximum development (maximum sea ice thickness) have decreased by 13 % in the Kara Sea, by 9 % in East Siberian Sea, by 5 % in the Laptev and Chukchi Seas in comparison with the previous period. The sea ice thickness development process has become much slower, transition between the sequential stages of development is shifted by 10–20 days (in some points 30–40 days) later. The surface air temperature is on average 2,7 °C higher than for the previous period at all sea stations. The most significant changes (1.4–6.1 °C) are observed in the autumn season (October–December), all the stations show the lowest difference in the summer months. Averaged over the stations, the sum of the frost degree-days (SFDD) decreased by 14 %; all 15 recent winter seasons can be classified as mild and none of the stations has experienced winters that meet the criteria of severe winter. The frequency of mild winters increased by 36–95 % by stations. The SFDD decline is in good agreement with the changes of the mean seasonal (November-May) and maximum SIT at the stations. In conclusion, it is noteworthy that the recent 15-year period (2005–2020) is distinguished by the mildest conditions.В работе проанализированы ряды данных по толщине припая и приземной температуре воздуха (ПТВ) наземных полярных гидрометеорологических станций, расположенных на побережье Российской Арктики. Проведено сравнение данных наблюдений за современный 15-летний период (2005–2020 гг.) с данными наблюдений до 2004 г. (с 1930–1940-х гг.). В результате выявлено, что с 2005 г. толщина припая на момент максимального развития уменьшилась на 13 % в Карском море, на 9 % в Восточно-Сибирском море, на 5 % в морях Лаптевых и Чукотском. Процесс нарастания стал значительно медленнее, а переход между возрастными градациями сместился на 1–2 декады на более поздний срок. С 2005 г. температура воздуха повысилась в среднем на 2,7 °C, при этом наибольший вклад в это вносит осенний период (октябрь–декабрь), а наименьшая разница по сравнению с предыдущими десятилетиями наблюдается в летние месяцы. Поскольку приземная температура воздуха является одним из определяющих факторов нарастания толщины льда, в работе рассмотрена ее корреляция с суммой градусо-дней мороза (СГДМ). В среднем по станциям СГДМ снизилась на 14 %; все рассматриваемые 15 зимних сезонов с 2005 г. можно классифицировать как мягкие, ни на одной из станций зимы не соответствовали критериям суровой или умеренной. Повторяемость мягких зим увеличилась на 36–95 % по станциям. Снижение СГДМ хорошо согласуется с изменениями среднесезонных значений (за ноябрь–май) и максимальных значений толщины припайного льда на станциях. В заключение следует отметить, что исследуемый 15-летний период (2005–2020 гг.) отличается самыми мягкими условиями за всю историю наблюдений на полярных станциях российских арктических морей

Оценка погрешности измерений средней высоты снежного покрова на леднике Альдегонда (Шпицберген)

This study introduces an empirical equation allowing to estimate an uncertainty of area-averaged snow depth on the Aldegondabreen Glacier, computed from standard snow surveys and made by an avalanche probe or by similar equipment. The two-decade history of the ongoing mass-balance monitoring program on this glacier shows that the methodology of field work on snow-measuring survey varies somewhat from year to year: the number and location of measurement points change. To identify and quantify long-term trends and variations in snow cover, it is crucial to assess the inter-comparability of the data in the obtained measurement series. The proposed equation was intended to solve this task basing on the collected data only, allowing to estimate the uncertainty even retrospectively. To build this equation, we applied a bootstrap statistical approach to the results of snow surveys carried out in Svalbard in 2015–2021. After interpolating the field measurements, obtained rasters were sampled sequentially with different numbers of points, simulating the real snow survey. The points were initially located in a form of a quasiregular grid and then randomly shifted between the iterations. After a thousand simulations for each number of points, the standard deviations were calculated relative to the “true” values, derived from corresponding rasters. These standard deviations, which we admit to be a random error of the area-averaged snow depth value, expectedly decrease with the number of sampling points and increase with the coefficient of variation ( ). The well-known index indirectly characterizes the irregularity of snow cover. After approximating the bootstrap results, the authors derived an equation that yields a relative error. The equation includes only two predictors which are the probing density per area unit and the , which potentially allows using it for the other glaciers. However, the universality of the empirically obtained coefficients is debatable, since they may vary due toa glacier size, its morphology and other parameters.Предложен метод оценки относительной погрешности средней высоты снежного покрова, получаемой на архипелаге Шпицберген по снегомерным съёмкам. Уравнение для оценки погрешности включает в качестве предикторов плотность промеров на единицу площади и коэффициент вариации высоты снега. Уравнение получено на основе результатов применения статистического метода бутстрэп к набору данных снегомерных съёмок 2015–2021 гг. на леднике Альдегонда

Analysis of the results of the operation to separate craniopagus twins, depending on the type of their fusion

The purpose of the study is to identify the presence or absence of a relationship between the type of fusion and the success of the operation.Цель исследования – выявить наличие или отсутствие зависимости между типом сращения и успехом операции

Внутрисезонная изменчивость абляции ледника Альдегонда (Шпицберген)

The intra-annual variability of the surface ice ablation on the 5.5 km2 Aldegondabreen glacier (Spitsbergen Island, Barentsburg area) is presented. The ice ablation was measured during five seasons (2018–2022) at the two stakes, installed in the lower part of the glacier and at the index site, where the amount of ablation numerically coincides with the glacier-averaged value with the r = 0.99 agreement. The temporal resolution of the ice ablation data is uneven and varies from 3 to 45 days. To carry out the correlation analysis, meteorological data from the automated weather station located near the glacier terminus are used. The ice ablation rates, obtained after normalization for the number of days between stake readings, have a tight correlation with both the air temperature and the downwelling shortwave radiation flux for most of the seasons, in 2018– 2021 (r = 0.71–0.99). Surface air temperature and short-wave radiation are closely related; the above estimates indicate the leading role of short-wave radiation in the summer ablation of the glacier in the period 2018–2021. The year 2022 became anomalous, as the correlation with the shortwave radiation significantly decreased (r = 0.21–0.34). The European heat wave of 2022, which also affected the Svalbard archipelago, interrupted the ordinary intra-annual variability of the air temperature, causing the unprecedented ice melt on Aldegondabreen in September. The predicted increase in frequency and intensity of the future heat waves will result in an increased role of turbulent fluxes in the surface energy balance of the low-elevated Svalbard glaciers. The article demonstrates how the empirically identified dependencies can change from season to season in a non-stationary climate.Рассмотрена зависимость внутрисезонной изменчивости абляции льда на леднике Альдегонда (Шпицберген) от приземной температуры воздуха и потока коротковолновой радиации. В 2018– 2021 гг. абляция льда хорошо согласуется с обоими факторами (r = 0.80–0.98 и 0.71–0.99 соответственно). 2022 год – аномальный с точки зрения нарушения связей абляции и радиации, что объясняется продолжительной волной тепла в Европе

Изменения объема и геометрии ледника Восточный Дальфонна (Шпицберген) в 2008–2019 гг.

Previously published geodetic mass balance data indicate glacier shrinkage in the Barentsburg area of Svalbard since the beginning of the 20th century on the decadal time scale. However, observations for shorter time spans allowing one to compute the inter-annual variability of the mass balance are scarce. The study presents results of ground-based GNSS and the GPR surveys of the Austre Dahlfonna glacier (2 sq km) located on Spitsbergen island, south of the town of Barentsburg. According to the GPR survey of spring 2019 at 50 MHz frequency, the area-averaged ice thickness was equal to 82 m, while the maximum was 170 m. The results confirm the polythermal structure of the glacier, with a layer of underlying temperate ice. Since the end of the Little Ice Age, the area of Austre Dahlfonna has halved. By comparing the GNSS survey results (the end of the melt season of 2019) with the co-registered archived remote sensing data (ArcticDEM strip of 2013 and S0 Terrengmodell of 2008), it was computed that, within the last 12 years (2008–2019), Austre Dahlfonna lost 16 % of its volume, which corresponds to a geodetic mass balance of –12.05 ± 0.85 m w. e. The mass loss in 2008–2013 (5.22 ± 0.37 m w. e.) was lower than in 2013–2019 (6.83 ± 0.48 m w. e.), which is in agreement with the ongoing direct measurements on the neighboring Austre Grønfjordbreen glacier and with the archipelago-wide mass-balance patterns. We demonstrate that the less intensive glacier mass loss, which occurred in 2005–2012 and was detected previously for the whole archipelago, definitely took place in the Barentsburg area as well. This time interval is characterized by the prevalence of a negative NAO phase (65 % of recurrence), which may indicate more frequent intrusions of colder Arctic air masses. This fact proves that the mass-balance variability of the Barentsburg area glaciers is governed in time spans of 5–10 years by regional-scale factors, presumably by shifts in the atmospheric circulation regimes.В работе представлены результаты топографической и геофизической съемок на леднике Восточный Дальфонна площадью около 2 км2, расположенном на архипелаге Шпицберген к югу от поселка Баренцбург. Средняя толщина льда по состоянию на 2019 г. составляет 82 м, максимальная — 170 м. На основе сравнения с архивными данными дистанционного зондирования показано, что за 12 балансовых лет ледник потерял 16 % своего объема, что эквивалентно потере массы в 12,05 ± 0,85 м в. э. Сравнением двух шестилетних периодов установлено, что в 2008–2013 гг. потеря массы замедлялась по отношению к последующему интервалу 2013–2019 гг., что согласуется как с наблюдениями на соседнем леднике Восточный Грёнфьорд, так и с общей масс-балансовой изменчивостью на архипелаге. Это приводит к выводу, что на временных интервалах порядка 5–10 лет изменчивость баланса массы ледников в районе Баренцбурга определяется факторами регионального масштаба, а именно сменами режимов атмосферной циркуляции на Шпицбергене, которые могут быть охарактеризованы преобладанием положительной либо отрицательной фазы индекса Северо-Атлантического колебания (NAO) летом

Measurements of π±\pi^\pm, K±K^\pm, pp and pˉ\bar{p} spectra in 40^{40}Ar+45^{45}Sc collisions at 13AA to 150AA GeV/cc

The NA61/SHINE experiment at the CERN Super Proton Synchrotron studies the onset of deconfinement in strongly interacting matter through a beam energy scan of particle production in collisions of nuclei of varied sizes. This paper presents results on inclusive double-differential spectra, transverse momentum and rapidity distributions and mean multiplicities of $\pi^\pm$, $K^\pm$, $p$ and $\bar{p}$ produced in $^{40}$Ar+$^{45}$Sc collisions at beam momenta of 13$A$, 19$A$, 30$A$, 40$A$, 75$A$ and 150$A$ GeV/$c$. The analysis uses the 10% most central collisions, where the observed forward energy defines centrality. The energy dependence of the $K^\pm$/$\pi^\pm$ ratios as well as of inverse slope parameters of the $K^\pm$ transverse mass distributions are placed in between those found in inelastic $p$+$p$ and central Pb+Pb collisions. The results obtained here establish a system-size dependence of hadron production properties that so far cannot be explained either within statistical (SMES, HRG) or dynamical (EPOS, UrQMD, PHSD, SMASH) models

Measurements of π+\pi^+, π−\pi^-, pp, pˉ\bar{p}, K+K^+ and K−K^- production in 120 GeV/cc p + C interactions

This paper presents multiplicity measurements of charged hadrons produced in 120 GeV/$c$ proton-carbon interactions. The measurements were made using data collected at the NA61/SHINE experiment during two different data-taking periods, with increased phase space coverage in the second configuration due to the addition of new subdetectors. Particle identification via $dE/dx$ was employed to obtain double-differential production multiplicities of $\pi^+$, $\pi^-$, $p$, $\bar{p}$, $K^+$ and $K^-$. These measurements are presented as a function of laboratory momentum in intervals of laboratory polar angle covering the range from 0 to 450 mrad. They provide crucial inputs for current and future long-baseline neutrino experiments, where they are used to estimate the initial neutrino flux

Search for the critical point of strongly-interacting matter in 40^{40}Ar + 45^{45}Sc collisions at 150A Ge V /c using scaled factorial moments of protons

The critical point of dense, strongly interacting matter is searched for at the CERN SPS in $^{40}$Ar + $^{45}$Sc collisions at 150A Ge V /c. The dependence of second-order scaled factorial moments of proton multiplicity distribution on the number of subdivisions of transverse momentum space is measured. The intermittency analysis is performed using both transverse momentum and cumulative transverse momentum. For the first time, statistically independent data sets are used for each subdivision number. The obtained results do not indicate any statistically significant intermittency pattern. An upper limit on the fraction of correlated proton pairs and the power of the correlation function is obtained based on a comparison with the Power-law Model developed for this purpose